4-(4-Fluorophenyl)-2-methyl-6-(5-piperidinopentyloxy)pyrimidine hydrochloride (hereinafter referred to as Compound A) is known to have a neurocyte necrosis inhibiting effect and thus to be useful as a medical drug (International Publication WO96/07641).
In a known method for producing Compound A (see Example 1 in the above-mentioned publication), because of oily characteristic and resulting difficulty in crystallization of 4-(4-fluorophenyl)-2-methyl-6-(5-piperidinopentyloxy)pyrimidine (free base of Compound A, hereinafter referred to as Compound 1) obtained by a reaction between the starting materials, 4-chloro-6-(4-fluorophenyl)-2-methylpyrimidine and 5-piperidino-1-pentanol, a column chromatography was employed to isolate and purify Compound 1, which is then converted into a hydrochloride, whereby obtaining Compound A. However, such isolation and purification by the column chromatography does not enable a large scale production of Compound A at a high purity, and is not suitable for an industrial manufacturing process. Accordingly, it has been demanded to develop an efficient method for obtaining a highly pure Compound A industrially at a high yield by a simple convenient procedure without employing a column chromatography.